Wrench with a flexible gripping band



Feb.'12, 1957 G. BRAM WRENCH WITH A FLEXIBLE GRIPPING BAND Filed Dec. 16, 1953 United States Patent 2,780,951 WRENCH WITH A FLEXIBLE GRIPPING BAND Georges Bram, Pont-a-Mousson, France, assignor to Compagnie de Pont-a-Mousson, Nancy, France, a French body corporate Y Application December 16, 1953, Serial No. 398,583

Claims priority, application France December 17, 1952 Claims. 01. 81-64) The invention has for object to provide a gripping wrench of the self-gripping type for rotating, for example for screwing or unscrewing, a cylindrical body having a smooth external surface such as a tube, pipe or the like, this wrench being simple in construction and particularly easy to use without Wasted motion in the rotation of said body.

This gripping wrench comprises in combination: a lever one of the ends of which forms a handle and the other end forms a first jaw, a second jaw pivotally mounted at one of its ends on this lever adjacent said first jaw and a deformable gripping band which is fixed at one of its ends to the free end of said first jawand is disposed in the space between the two jaws so as to form an open loop which extends at least to the free end of the second aw I Other features and advantages of the invention :will appear from the ensuing illustrative description with reference to the accompanying drawings given merely by way of example and in which: i

Fig. 1 is a side view of a first mode of carrying out the invention,

Fig. 2 is an end view thereof, the gripping band having been removed for the sake of clarity, v

Fig. 3 is a sectional view, on a larger scale, of the tightening band in its inactive non-gripping position,

Fig. 4 is a view of a portion of the inner face of the gripping band,

Fig. 5 shows a sectional view of a modification of the gripping band,

Figs. 6 and 7 are, respectively, a fragmentary side view and an end view (band removed) of a first modification of the wrench according to the invention.

In the embodiment shown in Figs. 1 to 4 the wrench according to the invention comprises a lever 1 in the form of a flat strip which is substantially rectilinear and forms at one of its ends a handle. At its other end 2, which is enlarged and slightly downwardly incurved, forms a first jaw which is fixed in that it may be rigidly secured to the lever bywelding, riveting or other means or may form part of the same material as this lever.

A second jaw 3, which has substantially the shape of an arc of a circle, is pivotally mounted at one of its ends, shaped in the form of a fork 4, on a projection 5, formed on the fixed jaw, by a means of a pin 6. The free end of the pivotal jaw includes two lateral lugs 7 which form a second fork. This jaw 3 is therefore capable of pivoting about the pin 6 and its free end may thus approach the end of the fixed jaw, which is also provided with two lateral lugs 8 identical to the lugs of the jaw 3.

Between the ends of the two jaws is fixed, by means of pins 9 and 10 extending through the lugs, a gripping band 11 which has substantially the shape of a Segment Patented Feb. 12, 1957 "ice stitute a portion of an arc whose diameter is substantially equal or preferably slightly less than the diameter of the cylindrical object T the Wrench is adapted to grip. The developed length of this blade is greater than half the 5 circumference of the object T. Preferably, the angle x pivot 6 in the direction opposite to that of arrow f1.

subtended at the centre. of curvature of this blade by the.

two looped ends of the latter is about 110". This blade is covered on its inner face with a covering or lining 15 of an elastic material, for example rubber which is moulded onto the blade and vulcanized. This lining 15 completely covers each hooking loop 13. It includes on its inner face projections 16 which are fairly shallow, of the order of 0.5 to 1mm. in depth and which include therebetween channels or other recesses 17.

The wrench is used and operates in the following manner:

Let it be assumed that a cylindrical pipe T is to be rotated, for example in the direction of arrow 1 (Fig. l), the wrench is gripped by the handle and is placed in position on the pipe. The wrench is held perpendicular to the pipe so that the movable jaw 3 extends from its The head of the wrench is pushed very slightly in the direction of arrow f so that the pipe separates the ends of the jaws, enters between the latter and is engaged by the gripping band 11. Owing to the resilience of the blade 12 the band closes around and slightly grips the pipe.

When the handle is urged in the direction of arrow P, the force exerted tends to close the jaws and bring together the pins 9 and 10. Thus the band is subject to tensile stress between the pins 9 and 10 and there is an increase in the pressure the lining 15 exerts on the surface .of contact with the pipe. The pressure of contact therefore increases with increase in the force applied to the handle. 1 and there'is thus obtained a self-grippingefiect Owing to the adherence of the band to the pipe, due to the high coefficient of friction of the lining 15 and projections 16, the pipe is rotated.

To rotate the pipe in the opposite direction to that of arrow f it suffices to reverse the disposition of the wrench elements with respect to the pipe.

Since as soon as the wrench is placed around the object to rotate the band closes around the latter, the object is rotated as soon as force is applied to the handle. In other words, the inactive angular displacement of the handle which is necessary in known-type wrenches to close the jaws on the object to rotate is eliminated. Water or other liquid is able to flow through the passageways between the projections 16 and the pipe T. This is an advantage in cases Where for example a pipe has to be rotated at the bottom of a water-logged excavation.

Fig. 5 shows a modification of the gripping band in which the reinforcement 12 of this band is embedded in the lining 15. This reinforcement comprises a blade which is so shaped as to form at its central portion an arc and at its ends two hooking eyes 13. Two end portions of the blade are folded back against the inner face of the arc and formed over so as to form fiat hooks or seams 18 which interengage. Hence in this arrangement when the band is gripping around the pipe or other object, the formed-over ends are gripped between the arced portion of the blade and the object and there is little risk of these ends separating. Furthermore, since the blade is completely embedded in the friction lining it is protected against rusting.

According to the embodiment shown in Figs. 6 and 7, the ends of the two jaws are devoid of lugs 7 and 8 and are simply provided with a portion which has a rounded end and the same Width as the gripping band 11*. In this example these ends are inserted in the ends of the gripping band which are curved to suit the shape of the jaw ends. ,The band is secured to the latter by screws 19 or any other adequate means. This modification ofiers the advantage of a reduced over all width of the wrench.

The wrench according to the above-described examples is more particularly suitable for rotating cylindrical objects having a diameter less than 50 mm.

Although specific embodiments of the invention have been described hereinbefore with reference to the accompanying drawings, it must be understood that modifications and changes may be made therein without dcparting from the spirit of the invention or the scope of the appended claims. Thus the gripping band may comprise transverse elements pivoted together, some of which may not include the friction lining or covering. Furthermore, the reinforcement of this gripping band may be of anykind and may be for example of metallic cloth such as chain mail. The inner face of the friction lining or covering may be formed in any other manner, for example it may comprise longitudinal, transverse or crossed grooves.

Having now described my invention what I claim as new and desire to secure by Letters Patent is:

1. A self-gripping wrench for gripping and rotating pipes and other objects having a smooth external surface, said wrench comprising in combination: a single lever having two ends, one of said ends forming a single handle for said wrench, and the other of said ends'forming a first jaw; a second jaw pivotally mounted at one of its ends on said lever adjacent said first jaw; a gripping band disposed inwardly of and between said two jaws, said band comprising a yieldable reinforcement forming a spring and a lining made of flexible and elastic material having a high' coefficient of friction, said gripping band having its two ends attached to the free ends of said two jaws; said gripping band having an inner surface forming an open loop in the space comprised between said two jaws, the angle subtended by the ends of said loop and measured from the center of curvature of said band being about 110".

2. Gripping wrench as claimed in claim 1, wherein the ends of the gripping band are formed over and rigidly secured to the ends of said jaws.

3. Gripping wrench as claimed in claim 1, wherein said jaws comprise eyes at their free ends, said yieldable reinforcement formed with two other eyes at the ends of the gripping band and two pivot pins are provided each one of which extends through the corresponding eyes of said jaws and said band ends which are in axial alignment, and these axes being parallel to the pivot axis of said second jaw on said first jaw.

4. Gripping wrench as claimed in claim 3, wherein the ends of said reinforcement of the gripping band are hooked together by means of interengaging seams and are so disposed as to adjoin a face of the central part of the reinforcement.

5. Gripping wrench as claimed in claim 3, in which said eyes of said yieldable reinforcement comprise loops formed by portions of said reinforcement substantially at the ends thereof, said portions being riveted to said reinforcement, the lining of said band covering said ends on external faces of said loops.

. References Cited in the file of this patent UNITED STATES PATENTS 338,731 Gillett Mar. 30, 1886 591,325 Charlet Oct. 5, 1897 697,977 Butford Apr. 22, 1902 1,006,348 Beran Oct. 17, 1911 1,446,619 Edwards Feb. 27, 1923 1,521,342 Thomas et al Dec. 30, 1924- 1,'620,170 Stephenson Mar. 8, 1927 1,760,167 Palmer May 27, 1930 1,887,152 Geisler Nov. 8, 1932 1,913,906 Swenson June 13, 1933 2,122,104 Martin June 28, 1938 2,221,056 Mason Nov. 12, 1940 

